1. Field of the Invention
This invention relates generally to a method and apparatus for conducting surveys, of highways, bridges, mines, demolition sites, and the like, and in particular, relates to a method and apparatus for performing video surveys, wherein the surveyed locations are video recorded for subsequent review and analysis at a centralized control station.
2. Description of the Prior Art
Video scanning and/or recording has been utilized in other areas, such as policing horse races and security systems. Video systems have also been utilized in connection with road striping apparatus. One such apparatus known in the art utilizes an electronic sight, the monitor screen for which is located in front of the steering wheel of the paint vehicle. Another such apparatus comprises a television camera mounted on a vehicle adapted to travel on a paved surface such that the camera has a field of view encompassing the paved surface, and a receiver for producing an image of the field viewed by the camera. A scale is on the surface of the screen of the receiver, and by adjustment of the vehicle and the camera thereon, the image can be so located with respect to the scale to position the camera in a determined position. A road marking mechanism, such as for painting road lanes, can be mounted on the vehicle to mark the road surface at a specific location. Although the apparatus is referred to as a "surveying" apparatus, that term is specifically limited to measuring a paved surface for dividing the same into lanes or the like.
By way of contrast with the foregoing, this invention provides a method and apparatus for conducting nearly every type of survey, and is not limited to a partially automated apparatus for painting highway center lines. The method contemplates making a video recording of all locations to be surveyed. Where highway construction is contemplated, this would include video recording both the highway, if one exists already, as well as the buildings and flora on either side of the proposed construction. Special note may be taken of particular circumstances, such as culverts, streams, bridges or the like.
In the normal course of survey work today, a preliminary survey, as described above, must be conducted by one or more senior engineers, as well as one or more technicians. It may even be necessary to make several preliminary surveys. The method taught by this invention provides a means by which such preliminary surveys may be conducted by technicians alone, and in some circumstances, by even one technician. The video recorded survey may then be viewed and analyzed by any of the senior engineers at their central office location. This represents a substantial cost savings for all survey teams, particularly those run by the various state and local governments. In order that the engineer or other person viewing the survey may be aware of actual distances, an overlay having one or more scales may be prepared, which correlates the geometric disposition of the recording means, that is, a predetermined control position, with respect to the surveyed locations and the size of the monitor means. A more direct method for preparing a scale requires that during the course of the survey at least one actual measurement be taken of one feature being surveyed, for example, the average width of a highway. When the survey is replayed, the playback may be interrupted so that the width of the highway may be marked on an overlay covering the screen. Since this distance is known from one actual measurement, the scale on the overlay may be marked accordingly. Thereafter, when any measurement of a survey location is desired, the overlay may be shifted and the distance measured. In the alternative, it is possible to prepare a plurality of grid-like overlays, with standardized sets of scales and dimensions making it unnecessary to move the overlay about.
An integral scale means may be provided by an apparatus for conducting video surveys, comprising a motor vehicle, means for video recording locations to be surveyed, means for removably mounting the video recording means on the motor vehicle, and a set of members mounted on the vehicle and projecting into the field of view of the video recording means, thereby providing a video recorded survey with integral scale means. It would still be desirable to take at least one actual measurement.
By utilizing the methods and apparatus taught by this invention, it is a relatively simple matter to compile a complete tape library of an entire road system or subsystem thereof. The system is particularly useful for the surveys needed in pothole repair and other highway maintenance. File records of highway conditions may be updated periodically as new surveys are performed. A basis is provided for compiling accurate statistical records with respect to repairs and maintenance, with the special advantage of having records showing the highway or other structure both before and after some damage has occured or some period of time has passed.